JP2878699B2 - Electronic camera and image recording method thereof - Google Patents

Description

The present invention relates to an electronic camera that records a still image using a recording medium such as a memory card.

(Prior Art) In recent years, a solid-state image sensor such as a CCD (Charge Coupled Device) and a rotating magnetic field have been used as alternatives to a conventional (still) camera that captures and records a still image by using the sensitivity of a photographic film. 2. Description of the Related Art An electronic camera that captures and records a still image using a recording medium has been commercialized. However, since this type of electronic camera uses a rotating magnetic recording medium, a driving device for driving the rotating magnetic recording medium relative to the recording head is required inside the camera, and the size of the camera is reduced. Is not very suitable. Therefore, as a system that does not require such a driving device and is advantageous for miniaturization, an all-solid-state electronic camera system that records an image signal on a memory card using a semiconductor memory has already been proposed by the present applicant (for example, Japanese Patent Application No. 61-163711). An example of a typical configuration of such an electronic camera system is shown in FIG.
Shown in the figure.

The image of the subject is formed by a lens 121, an aperture 122, and a color filter.
An image is formed on a CCD 126 serving as an image sensor via
It is photoelectrically converted at 6. The output signal of the CCD 126 is subjected to predetermined processing by a preprocessing circuit 127, converted to a digital signal by an A / D (analog-digital) converter 128, and recorded on the memory card 115. The signal of each pixel of the image sensor is digitized and stored in the memory card 115. The signal of each pixel of the image sensor is applied to the preprocessing circuit 12
At 7, predetermined processing such as amplification, white balance correction, and γ correction is performed as preprocessing.
The memory card 115 records the pixel data subjected to the preprocessing in the order according to the pixel arrangement. At the time of reproduction, the data recorded on the memory card 115 is set in a reproducer, subjected to necessary signal processing, D / A (digital-analog) converted, and input to a TV (television) monitor. Is displayed as an image. FIG. 13 shows a case 110, a release switch 111 for triggering a shooting operation, a battery 123 as a power supply, an aperture 122, and a shutter control circuit for controlling an electronic shutter operation.
124, a CCD drive circuit 125, and a monitor 130 are also shown. The CCD drive circuit 125 includes a shutter control circuit 124, a CCD 126,
This is a circuit for controlling and driving the preprocessing circuit 127, the A / D converter 128, and the memory card 115. Monitor unit 130
Is used as a finder by displaying a photographed image by a signal passed through the preprocessing circuit 127 at the time of photographing.

As described above, the method of recording data corresponding to each pixel of the solid-state imaging device on the memory card as it is is simple, for example, the number of pixels of the solid-state imaging device of an electronic camera,
If the recording conditions such as the arrangement of the color filters are different, the data arrangement in the memory card to be recorded also changes, so that the recorded memory card has compatibility with other devices,
That is, the compatibility between the electronic camera used for recording and the electronic camera having a different number of pixels of the solid-state image sensor, arrangement of color filters, and the like is lost.

Also, if the memory capacity required to record image data for one shot still image differs according to the recording conditions, the capacity may increase even if new image data is written to a recording area where image data of a certain screen has been deleted. There is a disadvantage that recording may not be possible due to a shortage.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned drawbacks. If the present invention is adopted, even if the electronic camera is different, the recording medium on which the image of the present invention is recorded can be reproduced by an arbitrary reproducing machine. The image can be reproduced, and the image can be recorded by selecting one of a plurality of image quality modes according to the user's preference or the like. The amount of information is changed according to the selected mode and recorded. An object of the present invention is to provide an electronic camera capable of increasing the number of images by changing the recording capacity per image of a medium and an image recording method thereof.

[Configuration of the invention]

(Means and Actions for Solving the Problems) An electronic camera according to the present invention includes a solid-state imaging device and optical color filters of a plurality of colors having different spectral characteristics arranged on the solid-state imaging device, and converts an image. An imaging unit that outputs an image signal; a unit that converts an image signal output from the imaging unit into a luminance signal and two color difference signals; a mode selection unit that selects one of a plurality of image quality modes; A signal conversion unit that processes the luminance signal and the two color difference signals according to one mode selected by the selection unit and outputs a signal having a different information amount; and outputs a signal output from the signal conversion unit to a recording medium. Recording means for recording.

Further, the recording medium used in the electronic camera of the present invention is composed of a semiconductor memory, and the memory area is divided into a plurality of blocks for each predetermined capacity. The image information is recorded by increasing the number of blocks used for recording the image information.

Further, the image recording method of the present invention includes an imaging step of photoelectrically converting an image via an optical color filter of a plurality of colors having different spectral characteristics and a solid-state imaging device to output an image signal, and an image signal obtained by this step. Into a luminance signal and two color difference signals, a mode selection step of selecting one of a plurality of image quality modes, and the luminance signal and the two color difference signals according to the one mode selected in this step. It comprises a signal conversion step of processing a color difference signal to output a signal having a different information amount, and a recording step of recording the signal obtained in this step on a recording medium.

Hereinafter, an embodiment of an electronic camera according to the present invention will be described with reference to the drawings.

An electronic camera system includes an electronic camera and a playback device. The former, that is, the electronic camera, is a device that captures and records an object using a semiconductor memory card as a recording medium, and the latter, that is, the player, reads out image information recorded on the memory card from the memory card,
(Television) A device for displaying an image on a receiver or the like.

FIG. 1 is a perspective view of the electronic camera as viewed obliquely from behind, and a description of parts having the same functions as a normal camera will be omitted. The electronic camera 10 is provided with a release 11, an imaging mode changeover switch 12, and an imaging number display unit 13. Further, the electronic camera 10 is provided with an insertion slot 14 for inserting and removing the semiconductor memory card 15 from the right side. Further, the electronic camera 10 is provided with a shutter speed selection dial 18. Each of these parts will be described later in detail.

FIG. 2 shows a schematic basic configuration of the electronic camera 10. At the time of imaging, focusing is performed by operating the lens system 21 and the shutter speed is selectively set by operating the shutter speed selection dial 18 as in a normal camera. The aperture is adjusted by controlling the aperture 22 by the control circuit 24. In the electronic camera 10, adjustment of a shutter speed by a so-called electronic shutter is used. In the electronic shutter, the shutter speed is adjusted by controlling the charge accumulation time of the CCD array 26 as an image sensor. An image of a subject is formed on the CCD array 26 via the lens system 21.

When the imaging operation is started and the release 11 is half-pressed (a state in which the release button is half pressed down) by an operator or a user's operation, the power supply voltage from the power source 23 using a battery is supplied to each electronic circuit. Supplied to the department. The amount of incident light is measured by the exposure sensor 19, and the control circuit 24 controls the diaphragm 22 according to the amount of incident light. The external color temperature is measured by the white balance sensor 17, and the control circuit 24 generates a white balance control signal according to the measured color temperature.

When the release 11 is further depressed and changes from a half-pressed state to a fully-pressed state (a state in which the release button is sufficiently depressed), the control circuit 24 generates a shutter pulse. The drive circuit 25 responds to the shutter pulse and
6, preprocessing circuit 27, A / D conversion circuit 28 and signal processing circuit 31
To the control signal. The CCD array 26, the pre-processing circuit 27, the A / D conversion circuit 28, and the signal processing circuit 31 operate in response to this control signal. An image information signal composed of an analog signal output from the CCD array 26 is supplied to the A /
The signal is supplied to a D conversion circuit 28, and is converted into a digital signal by the A / D conversion circuit 28. The digitized image information signal is
Further, the signal processing circuit 31 performs predetermined signal processing. The digital image information signal output from the signal processing circuit 31 is supplied to the semiconductor memory card 15 together with a control signal including an address signal. In this way, the image information signal of the captured still image is stored in the semiconductor memory card 15 as a digital signal.

The user can selectively set the format of data to be stored in the semiconductor memory card 15 by operating the mode switch 12 prior to imaging. Mode switch 12
Is to select and set a desired mode from a plurality of modes having different image qualities. By selecting the mode with the mode switch 12, the amount of digital data required to store one frame of image to be stored (hence, 1 The number of frames of an image that can be stored in one memory card 15 can be changed. For example, when the mode 1 is set as the high image quality mode, an image of one bloom is stored as digital data of 640 Kbytes with high image quality. In the mode 2, the image of one frame is 320 Kbytes and has the highest image quality after the mode 1. In mode 3, one frame image is 160K
Bytes are stored with the highest image quality next to mode 2, and in mode 4, which is the mode with the lowest image quality, an image of one frame is stored with 80 Kbytes and the smallest memory space per frame. For example, 2.56
If an M-byte memory is installed, 4 flashes per memory card 15 in mode 1 depending on the image quality selected.
Frames, 8 frames in mode 2, 16 frames in mode 3, and 32 frames in mode 4 can be stored. Details of this method will be described later.

FIG. 3 shows a basic configuration of the memory card 15. The memory card 15 is configured by a printed board on which a plurality of RAM (random access memory) chips 36 are mounted. One end of the memory card 15 has external terminals 32 including a data terminal, an address terminal, and a control terminal.
And a power supply terminal 33 are provided. The memory card 15 is used by being loaded into the electronic camera 10 or a playback device. The supply of the power supply voltage to the memory card 15 is performed via a power supply terminal 33, and the input and output of signals to and from the memory card 15 are performed via an external terminal 32. Memory card
The device 15 has a built-in battery 34 for storing stored data. The memory card 15 is provided with a power supply switching circuit 35. When the memory card 15 is loaded in the electronic camera 10 or the playback device, the power of the RAM chip 36 is supplied to the built-in battery 3
The power is switched from 4 to the power supply 23 of the electronic camera 10.

FIG. 4 shows a memory card 15 using 20 1-Mbyte RAM chips 361 to 3620 as a more specific example of the memory card 15. External terminals 321 to 323 and a power supply terminal 33 are provided at one end of the memory card 15. The external terminals 321 to 323 are an 8-bit data terminal 321 and an address terminal 32 for receiving address information A0 to A20.
2 and a control terminal 322. The memory card 15 in FIG. 4 has a capacity of 20 Mbits (2.56 Mbytes). The control terminal 323 is a terminal C for selecting the RAM chip 36.
S, a terminal WP for write pulse, and a terminal CE for card selection when there are several reproduction cards. One of the decoders 121 1 and 121 2 is selected by the input from the terminal CS. The decoder 121 1 has a RAM chip 36 1 to 36 1
0, and the decoder 121 2 has a RAM chip 36 11-36 20
It corresponds to.

For example, a CCD array 26 which is a solid-state image sensor is used as an image sensor for capturing a frame image of a still image. As the CCD array 26 used in the electronic camera of the present invention, for example, a frame interline type CCD array is suitable.

FIG. 5 shows a schematic configuration of an example of a frame interline type CCD solid-state imaging device.

In this CCD array, pixel light receiving units 51 each composed of a photoelectric conversion element such as a photodiode are two-dimensionally arranged.
A vertical transfer section 52 is provided adjacent to the column of the pixel light receiving sections 51 of each column. The charge of each pixel light receiving unit 51 is transferred to a corresponding vertical transfer unit 52 by a field shift pulse φv1, and transferred to a charge storage unit 54 as a frame memory unit via a transfer gate 53. The signal charge of the charge storage unit 54 is output as an electric signal from the output circuit 56 via the horizontal transfer unit 55. A sweeping unit 57 is provided at the other end of the vertical transfer unit 52.

In order to obtain a color image signal using only one CCD array, an optical element for separating light components of, for example, R (red), G (green) and B (blue) is provided on each pixel light receiving unit 51. One color filter is arranged. Various configuration examples are known for types and arrangements of optical color filters, and the electronic camera of the present invention is not limited to a special type.

The electronic camera 10 according to the present embodiment will be described in detail with reference to FIG. 6, which shows a more specific configuration.

Before pressing the release 11, the user can operate the mode switch 12 to select a desired mode in consideration of the image quality to be stored in the memory card and the number of frames stored in the memory card. The selected mode signal is sent from the central processing unit (CPU) 24 1 to the switch 31 5
Is input to

When the release 11 is pressed to the half-pressed state, the information on the external color temperature and the information on the exposure amount from the white balance sensor 17 and the exposure sensor 19 are transmitted to the C via the I / F 242, respectively.
Input to PU24 1. Based on the information of the exposure amount, CP
The U 241 controls the drive of the aperture 22 via the aperture drive circuit 245. Further, the CPU 241 receives a command via the interface (I / F) 243 and the signal generator 251 based on the information for the white balance and the information on the exposure amount.
The CD drive circuit 252 is controlled, and the CCD drive circuit 252 controls C
The drive of the CD array 26 is controlled. In addition, I / F
The flash drive circuit 244 is controlled by a signal supplied through 243, and the flash drive circuit 244 is used during imaging.
But flash 16 like electronic flash
Drive or not drive is set. The amplifier circuit (amplifier) 271 and the color separation / γ correction / white balance circuit 272 each include a signal supplied from the CPU 241 via the I / F 243 and a signal supplied from the CPU 241 to the I / F 243 and the signal generator 25. And is controlled by a signal provided through one.

Next, when the release 11 is further depressed and fully pressed, the CCD array 2 is
6, amplifier 271, color separation / γ correction / white balance circuit 272, A / D conversion circuit 28, signal processing circuit 311, filter 3
1, 2, sub-sampling circuit 313, data compression circuit 314, switch 315, and memory interface (memory I / F) 3
The drive signal corresponding to each element is supplied to 17.

In response to the operation of the relays 11, an image information signal is output from the CCD array 26. The image information signal is amplified to a predetermined level by an amplifier 271, and further passes through a color separation / white balance / γ correction circuit 272 comprising a color separation circuit, a white balance circuit, and a γ correction circuit, so that the R, G, and B signals are converted. The signals are input to the A / D converter 28 in parallel. The R, G, and B digital signals output in parallel from the A / D converter 28 are converted into a luminance signal Y1 and color difference signals CR1 and CB1 by a signal processing circuit 311. 2) The two types of color difference signals CR1 and CB1 are input to the reduction filter 312 with the number of samples being halved. The luminance signal Y1 and the color difference signals CR1 and CB1 are linearly quantized data with one sample being 8 bits. The relationship between the sample points of the luminance signal Y1 and the sample points of the color difference signals CR1 and CB1 is the seventh.
As shown in the figure. The reduction filter 312 is a pre-reduction filter for sub-samples. The luminance signal Y1 and the color difference signals CR1 and CB1 are provided to a sub-sampling circuit 313 after passing through a reduction filter 312. Sub-sample circuit 31 3
In, the luminance signal is subjected to line offset sub-sampling to become a luminance signal Y2 with a sample number of 、, and a chrominance signal CR1.
And CB1 are sub-sampled every other line, and become the color difference signals CR2 and CB2 whose number of samples is further reduced to 1/2. The relationship between the sample data points at this time is as shown in FIG. The luminance signal Y2 and the color difference signals CR2 and CB2 are input to the data compression circuit 314. As already mentioned, the luminance signal Y
2. Each of the color difference signals CR2 and CB2 is linearly quantized at 8 bits per sample.
The number of data bits in the sample is reduced. In this embodiment, data compression is performed using, for example, DPCM (differential pulse code modulation) as a data compression method. Data compression by DPCM is a well-known technique, in which the difference between sample data and the immediately preceding sample data is nonlinearly compressed and quantized. For example, for the luminance signal Y12 in FIG.
The difference between the luminance signals Y11 and Y12 is nonlinearly quantized, and one sample is represented by 4 bits or 2 bits. Similarly, the color difference signals CR2 and CB2 are also compressed, and one sample becomes four.
It is represented by bits or 2 bits. The luminance signal thus compressed is referred to as Y3, and the color difference signals are referred to as CR3 and CB3.

The switch 315 is provided for selecting a luminance signal and a color difference signal according to the set mode. For example, when the mode (A) is selected, the signal processing circuit 31
Signals Y1, CR1 and CB1 output from 1 are switches 31 5
And is stored directly in the memory card 15 via the buffer memory 316. Similarly, in mode (B), signals Y2, CR2 and CB2 from sample circuit 313 are:
In the mode (C), the signals Y3 and CR3, which are compressed by the data compression circuit 314 and represented by 4 bits per sample,
If CB3 is in the mode (D), the data compression circuit 31
The signals Y3, CR3, and CB3 compressed by 4 and represented by 2 bits per sample are selected by the switch 315, respectively. The signal selected by these switches 315 is
The data is stored in the memory card 15 via the buffer memory 316.

In addition to the image data, information on which mode is selected is stored in the memory card 15 at the same time as the image data.
(For example, "001" for mode (A) and mode (B)
Is stored in a binary code indicating the mode number, such as "010". Further, in the memory card 15, for example, image data such as presence / absence of use of a flash, white balance control data, exposure data (or aperture data), and shutter speed data may be stored in a binary code as in the mode. Is also possible. These pieces of information are displayed on the display unit 13 by the CPU 241, and the user, that is, the operator, can check the information on the display unit 13.

FIG. 9 (a) shows a method of recording data on the memory card 15.
This will be described in detail with reference to (e). Here, as shown in FIG. 4, 20 Mbits in which 20 1 Mbit RAMs, for example, SRAM (static RAM) are mounted, that is, 2.56
An example in which an M-byte memory card is used will be described.

As shown in FIG. 9A, the entire memory space is divided into a directory area, a FAT (file allocation table) area, and a data area. In the directory area, as shown in FIG. 9 (b), a file number, ie, information indicating an image (frame) number when the file is image data,
Information indicating information classification, that is, classification of image data, audio data, or other data, and image method, that is, image
Information indicating whether the system is 525/60 or 625/50, information indicating the image mode, that is, information indicating the image compression method (including the non-compression mode), information indicating the audio mode, ie, the compression method in the case of audio data, and recording (imaging) ) Information indicating the year of recording, information indicating the month of recording, information indicating the date of recording, information indicating the time of recording, and information indicating the amount of recording are each written in 1 byte, and the file (image data file) is The starting data block number (entry block number) and the number of data blocks used for storing the file are written. In this directory area, 16 bytes are prepared for each file, and 256 files (256 frames for images) are allocated. Therefore, the directory area is 4 KByte. FIG. 9C shows the configuration of the FAT area, and FIG. 9D shows the configuration of the data area. Prepare 256 bytes in the FAT area and assign addresses from 00H to FFH. The data area is divided into blocks of 10 Kbytes, and block numbers 00H to FEH are assigned to each block.

For simplicity of explanation, it is assumed that about 40 Kbytes are required to record one frame of data, for example. In this case, for example, the entry block number is written as 11H and the number of used blocks is written as 04H in the directory area. 11H in FAT area
Write 12H to the address, 13H to the 12H address, 2AH to the 13H address, and FFH to the 2AH address. The image data of one frame is composed of block numbers 11H, 12H, 13H and 2 in the data area.
It is written to the 40K byte area linked to AH. FAT
FF H written to address 2A H of the area indicates the last block. FIG. 9E shows a 40 Kbyte memory area to which the blocks are linked. In the first block, that is, 256 bytes of block number 11H, data of imaging conditions including the use of flash, white balance data, exposure value (or aperture value), and shutter speed value are recorded, and the remaining 252 bytes include, for example, a title. Etc. is left as a user area for recording. Image data is continuously recorded from the 257th byte to the block number 2AH. 64 blocks in mode (A), 32 blocks in mode (B), 16 blocks in mode (C),
In the mode (D), eight blocks are used respectively.

In this method, recording on a memory card can be performed without any problem even when variable-length encoding in which the required memory capacity after encoding differs for each frame is used. That is, after encoding, data is temporarily stored in the buffer memory 316. Since the memory capacity necessary for recording one frame of data can be determined by the use status of the buffer memory 316, it is also possible to calculate how many data blocks to use based on the memory capacity. When the number of unused blocks in the memory card is insufficient, the image data is kept stored in the buffer memory 316 so that the next imaging cannot be continued unless a new memory card is inserted.

The processing procedure for performing such recording will be described in detail with reference to the flowchart of FIG.

When an operation input of the release 11 for determining an imaging timing is given (step ST1), imaging information to be written into a directory area of the memory card 15, for example, mode information, information on whether a flash is used, white balance information, exposure value (Or aperture value) information, shutter speed information, year information, month information, day information, time information, and directory information of the attached memory card 15 are fetched (step ST2). The entry block number of the memory card 15 is set based on these information (step ST3). Further, based on the mode information, the number of data blocks used for storing a captured image is obtained (step ST4). Installed memory card 1
The storage capacity of 5 is checked, and if the necessary number of data blocks for storing an image cannot be secured in the memory card 15 (step ST5), the display is performed by the display unit 13 or an appropriate alarm (for example, a buzzer). The user is prompted to replace the memory card 15, and if a new memory card 15 is not inserted (step ST8), the process is stopped. When a new memory card 15 is inserted (step ST8),
Return to step ST2. If the required number of data blocks for storing images can be secured in the inserted memory card 15 (step ST5), the F of the memory card 15
Assign an AT address (step ST6),
The image data and the above-described imaging information are stored in the memory card 15 (step ST7).

Next, the image data is read from the memory card 15 and the TV
A reproducing device for displaying an image on a monitor or the like will be described with reference to FIG.

Insert the memory card 15 into the player 90 and
When the file number (image number) is designated by the operation of 4, the CPU (central processing unit) 102 reads out the information of the directory area of the memory card via the card interface (card I / F) 91. The CPU 102 confirms whether or not the information classification of the designated file number is image data, what the image method is, and what the compression mode is, and recognizes the entry block number. Next, the CPU 102 reads information of all block numbers from the FAT area. The block number is given to the card I / F 91 from the CPU 102, and the card I / F 91
Generates an address corresponding to a block number and reads out image data one byte at a time. Further, the CPU 102 controls a signal processing path according to the image system and mode information read earlier. For example, when the mode is the mode (C), the data compressed to 4 bits is returned to 8-bit linear quantized data by the data restoration circuit 92, and when the mode is (D), the data is returned from 2 bits to 8 bits. In the modes (A) and (B), the read image data is input to the interpolation circuit 94 without passing through the data restoration circuit 92. The luminance signal Y and the two color difference signals CR and CB are output from the interpolation circuit 94, and one frame of data is written into the frame memory 95. In the modes (C) and (D), the image data is stored in the data restoration circuit 92 and the interpolation circuit.
The data is written to the frame memory 95 via 94.

The route control according to the above-described mode is performed as follows.

The mode signal output from the card I / F 91 is input to the determination circuit 100 via the CPU 102, and the mode is determined by the determination circuit 100. The state of the switch 106 is switched according to the determination result in the determination circuit 100, and the operations of the data restoration circuit 92 and the interpolation circuit 94 are also switched and controlled.

Data other than the image data output from the card I / F 91 is stored in the frame memory 95 via the data circuit 93.
It is stored similarly to the image data. After one frame of data is written to the frame memory 95,
Is supplied with a read clock from the signal generator 103, and the luminance signal Y and the color difference signals CR and CB are read. The luminance signal Y and the color difference signals CR and CB are respectively D / A
The (digital-analog) converter 96 returns the signal to an analog signal, and the input method of the TV monitor 107 is R (red),
In the case of the G (green) and B (blue) input methods, analog R, G, and B signals are generated by the matrix circuit 97 and input to the TV monitor 107. If the input method of the TV monitor 107 is the NTSC composite input method, the analogized luminance signal Y and color difference signals CR and CB are output to the first encoder.
The signal is converted into a composite signal by the second encoder 98 and the second encoder 99 and input to the TV monitor 107. If the input method of the TV monitor 107 is the YC separation input method, the analogized luminance signal Y and color difference signals CR and CB are converted to the first encoder 98.
Is converted into a luminance signal Y and a color signal C by the TV monitor 10.
Entered in 7.

As described above, the image captured and stored in the memory card 15 can be displayed. Of course, if output terminals such as R, G and B output terminals are connected to, for example, a video printer, it is possible to take a hard copy.

Next, in the system of the present invention, the recorded image can be erased frame by frame. The deletion of the image for each frame is performed as follows.

When the player 104 operates the keyboard 104 to specify an image number and issues an erase command, the CPU 102 searches the directory area of the memory card 15 via the card I / F 91 and matches the specified image number. (File number)
Is searched. When the specified image number is found,
FFH is written in the image number, entry block number, and used block number areas of the corresponding directory.
Further, the stored contents of the address used in the FAT area are erased (00H is written to all the corresponding addresses).

In addition, when an image of one frame is additionally recorded in the electronic camera, the FAT area is searched (under the control of the CPU 241), and the address where 00H is written is searched. The smallest address in which 00H is written is set as the entry block number, the required number of blocks is calculated from the memory capacity required for storing one frame, and the address for linking the block to the FAT area is written. Next, the empty directory (file number
FF H), data such as a file number and an information classification are written in one of them, and the entry block number and the number of used blocks are written in the last two words. After that, imaging condition data and image data such as whether or not a flash is used are sequentially written into the linked blocks.
As a result of searching the FAT area, if the number of blocks is insufficient for storing an image, a signal indicating that writing is not possible is generated, and a warning indicating that writing is not possible is displayed on the display unit 13 by the signal, for example. You. This warning, for example, LED
(Light emitting diode) may be displayed by lighting.

In the above description, the case where one block is 10 Kbytes has been described as an example. However, when the memory capacity required for recording one frame of image data changes minutely, the size of one block may be reduced. Alternatively, the minimum memory capacity required for recording one frame may be one block.

In the above description, the luminance signal Y and the two color difference signals CR and
Although the case where CB is used has been described, RY and BY signals may be used as color difference signals. These signals Y, RY and BY are derived from the R, G and B signals as follows: Y = 0.30R + 0.59G + 0.11B R-Y = 0.70R-0.59G-0.11B BY = -0.30R-0.59 It can be easily converted as G + 0.89B. Similarly, it is also possible to use I and Q signals as two color difference signals.

Further, in the above description, the case of compressing data using DPCM to reduce the bit capacity of one sample has been described.
Such data compression includes various methods depending on a difference in a method of generating a prediction signal or a method of selecting a quantizer for nonlinear quantization, or transform coding.
There are many methods, such as the method using. Whatever method is used, it is possible to cope by storing information indicating which method is used as mode information in the memory card as binary data.

FIG. 12 shows a configuration according to another embodiment of the present invention. In this embodiment, the A / D in FIG.
Conversion circuit 28, signal processing circuit 311, filter 31 2, sub-sampling circuit 31 3, data compression circuit 314, and switch 31
5 consists of a mixer circuit 41, an A / D conversion circuit 28 ', and a YC
The processing circuit 42, the filter 312 ', the data compression circuit 314' and the switch 315 'are replaced. In this embodiment, R, R output from the color separation / γ correction / white balance circuit 272 are used.
The G and B signals are combined by a mixer circuit 41, then digitized by an A / D conversion circuit 28 'and applied to a YC processing circuit 42, and the luminance signal and color difference signal output from the YC processing circuit 42 are filtered by a filter 312'. To the data compression circuit 314 '. The input and output of the data compression circuit 314 'are switches 315'.
Is selected.

〔The invention's effect〕

In the electronic camera according to the present invention, an image signal is converted into a luminance signal and two color difference signals, and an image cannot be reproduced from data read from a recording medium due to a difference in the number of pixels of an image sensor and a color filter arrangement. The inconvenience does not occur. In addition, an image can be recorded by selecting one of a plurality of image quality modes according to the user's preference. Furthermore, in the recording medium used in the electronic camera of the present invention, the memory area is divided into a plurality of blocks each having a predetermined capacity, and the number of used blocks is changed according to the selected image quality mode. Can be increased. Therefore, according to the present invention, it is possible to provide a user-friendly electronic camera, a recording medium used in the electronic camera, and an image recording method thereof.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of an electronic camera according to an embodiment of the present invention, FIG. 2 is a diagram showing a schematic configuration of the electronic camera of the embodiment, and FIG. 3 is used for the camera of the embodiment. Perspective view for explaining the basic configuration of a semiconductor memory card to be
FIG. 4 is a configuration diagram for explaining a more detailed configuration of the memory card, FIG. 5 is a diagram showing a schematic configuration of a CCD array used in the embodiment, and FIG. 6 is an electronic camera of the embodiment. FIG. 7 is a configuration diagram showing the configuration shown in FIG. 2 in more detail, and FIGS. 7 and 8 are diagrams for schematically explaining sample points of image data in the embodiment as positions on a two-dimensional plane. FIG. 9 is a view for explaining a recording format in a memory card in the embodiment, FIG. 10 is a flowchart showing a detailed procedure of processing at the time of imaging in the embodiment, and FIG. 11 is a camera of the present invention. FIG. 12 is a configuration diagram showing a schematic configuration of a reproducing device for reproducing an image captured by a memory card from a memory card, FIG. 12 is a configuration diagram showing a detailed configuration of another embodiment of the present invention, and FIG. It is a figure for explaining a camera. 11 Release, 12 Mode switch, 15 Memory card, 16 Flash, 17 White balance sensor, 19 Exposure sensor, 21 Lens, 22 Aperture,
24 ... Control circuit, 25 ... Drive circuit, 26 ... CCD array, 2
7 Pre-processing circuit, 28 A / D converter, 29 Data recording circuit, 31 Signal processing circuit.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akihiko Sugikawa 1 Toshiba Research Laboratory, Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Prefecture (56) References JP-A-63-274289 (JP, A) JP-A-64-72688 (JP, A) JP-A-62-269581 (JP, A) JP-A-63-146583 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04N 9 / 79-9/808 H04N 5/91-5/956

Claims (8)

(57) [Claims] 1. An image pickup device comprising: a solid-state image pickup device; and optical color filters of a plurality of colors having different spectral characteristics arranged on the solid-state image pickup device, and converting an image to output an image signal. Means for converting the output image signal into a luminance signal and two color difference signals, mode selecting means for selecting one of a plurality of image quality modes, and the mode selecting means for selecting one of the plurality of image quality modes. A signal converting unit that processes a luminance signal and two color difference signals to output signals having different amounts of information; and a recording unit that records a signal output from the signal converting unit on a recording medium. Electronic camera. 2. The electronic camera according to claim 1, wherein the signal conversion means has a mode in which the luminance signal and the two color difference signals are data-compressed and supplied to the recording means. 3. The electronic camera according to claim 1, further comprising data recording means for recording, on a recording medium, data indicating one mode selected by the mode selection means. 4. The electronic camera according to claim 1, further comprising a buffer memory for temporarily storing a signal in association with the signal conversion means. 5. The semiconductor memory according to claim 1, wherein the memory area is divided into a plurality of blocks for each predetermined capacity.
A removable electronic camera recording medium, characterized in that, when an image quality mode with a large amount of information is selected in the electronic camera described above, the number of blocks used for recording one frame of image information is increased. 6. An imaging step of photoelectrically converting an image via an optical color filter of a plurality of colors having different spectral characteristics and a solid-state image sensor to output an image signal, and converting the image signal obtained in this step into a luminance signal and a second signal. Converting into one color difference signal, selecting one of a plurality of image quality modes, and processing the luminance signal and the two color difference signals according to the one mode selected by this step. An image recording method for an electronic camera, comprising: a signal conversion step of outputting signals having different amounts of information, and a recording step of recording a signal obtained by this step on a recording medium. 7. An image recording method for an electronic camera according to claim 6, wherein said signal conversion means has a mode in which a luminance signal and two color difference signals are respectively compressed and supplied to a recording means. 8. The image recording method for an electronic camera according to claim 6, further comprising a data recording step of recording data indicating one mode selected by the mode selection step on a recording medium.